Immunity against micro-organisms 



321 



first a transitory phagolysis is induced, this being soon replaced by a 

 very considerable afflux of leucocytes, which is maintained for 24 hours 

 or longer, and then gives place to the normal condition. It is during 

 the period of the greatest leucocytosis 

 of the peritoneal fluid that the animal 

 exhibits the most marked resistance 

 against infective micro-organisms. 

 The vibrios are rapidly ingested 

 by the phagocytes, without having 

 previously been acted upon by the 

 " humours." Bordet shows that the 

 same thing happens in the case of 

 the streptococcus inoculated into 

 guinea-pigs after a protective injec- 

 tion of peptonised broth. 



We have observed the same phe- 

 nomenon in guinea-pigs and white 

 rats inoculated with the cocco- 

 bacillus of plague. Treated with 

 freshly prepared peptonised broth macrophage from guinea-pig. 



[337] 



FIG. 43. Macrophage 

 from guinea-pig 

 filled -with plague 

 bacilli. 



FIG. 44. Macrophage 

 from guinea-pig 

 containing plague 

 bacilli which are 

 commencing to es- 

 cape from the pro- 

 toplasm. 



FIG. 45. Macrophage from guinea- 

 pig which has burst as the result 

 of the development of plague bacilli 

 within it. 



the day previous to inoculation, these animals oppose to the micro- 

 organism a much more marked resistance than do the control animals. 

 The injection of the cocco-bacillus of plague sets up a marked phago- 

 B. 21 



